The present invention relates to a battery charging device for adjusting charge current based on hysteresis of charge.
Battery packages are being presently used that accumulate rechargeable batteries therein that may be repeatedly used as power sources for use in power tools or the like. The battery charging device performs charge at, for instance, a constant current when the battery package is attached and terminates charge when full charge is detected on a basis of, for instance, a changing pattern of battery voltage.
However, since standardized charge is performed in the above battery charging device in accordance with a set program, it would be the case that the life of batteries was remarkably shortened when operations were performed that did not meet an original handling method. For instance, in case an user would insert batteries that have hardly been used into the charger and batteries which capacities have been consumed only by a slight amount were repeatedly charged, the internal pressure of batteries would be further increased by repeatedly generating gas in batteries which are increased in pressure owing to gas generated in the interior thereof immediately before full charge is achieved, and electrodes would be damaged to thereby shorten the life of the batteries.
In order to cope with such subjects, the inventors have devised a method in which the charge current is adjusted based on past charging actions by making the battery charging device perform hysteresis learning. More particularly, when handling methods were repeated in the past through which the life of batteries are shortened, such situations were coped with by decreasing the charge current. However, various requests are being made by users, and it is also expected that one prefers shortening the charging time rather than prolonging the life of batteries.
The present invention has been made for solving the above subjects, and it is a purpose thereof to provide a battery charging device with which it is enabled to use batteries for a long period irrespective of handling methods of users.
The present invention further aims to provide a battery charging device with which batteries may be charged in accordance with handling methods of users.